1. Field of the Invention
The present invention relates to navigation devices that are capable of route search from a departure point to a destination using road data and navigation road data creating devices.
2. Description of the Related Art
In conventional navigation devices installed in vehicles such as automobiles, a technology is being disclosed, in which a route where it is possible to drive smoothly and travel speed is high in an actual drive is searched based on factors that may adversely affect ease of driving and the travel speed. For example, Japanese Patent Application; Publication No. JP-A-3894017 is referenced.
In the technology of Japanese Patent Application; Publication No. JP-A-3894017, a plurality of links having the same road attribute are extracted from a consecutive and the same line (i.e., a road length), the extracted plurality of links in one and the same road are combined and grouped, it is determined whether the group of links meet a condition to be determined as a high speed road, and high speed road information is created toward the group of links determined as the high speed road.